One of the tasks involved with maintaining a space telescope while the telescope is in a space environment is the replacement of spent components, such as batteries, and resupply of cryogenic components, such as liquid helium. These replacement components and supplies are stored in the cargo bay of the Space Shuttle and tansported to a point in space adjacent the telescope. A Remote Manipulator Arm mounted in the cargo bay is equipped with a bar or rod which, in a typical case, has three clamping and unclamping devices mounted to the bar in a manner which allows the clamping and unclamping devices to be adjustable across the length of the bar and also to be rotatable once positioned on the bar.
When smaller components of the telescope are to be replaced, two of the devices are clamped to a lifting handle of two discrete components, leaving the third device empty. The Remote Manipulator Arm is then operated to lift the two components out of the cargo bay and position them near the telescope. Once in position, an astronaut removes a spent component and clamps it to the empty device and thereafter removes a replacement component from the bar and inserts it into the telescope. This process is repeated, leaving two spent components clamped to devices on the bar, with these spent components being replaced in the cargo bay for return to Earth, where the components are refurbished or discarded.
Larger components, some being approximately the size of a phone booth and possessing a substantial amount of mass, are equipped with a plurality of lifting handles (typically three), with at least one of these handles being oriented out of plane to the others for stability. In this case, the devices on the bar are adjusted along the length of the bar and rotated to match the configuration of lifting handles on the component to be replaced. After this is accomplished, the Remote Manipulator Arm is operated to position the bar adjacent the telescope, where an astronaut removes the spent component and clamps it to the devices on the bar. The spent component is then moved to the cargo bay and stowed, after which a replacement component is clamped to the devices and positioned near the telescope. An astronaut then unclamps the replacement component and inserts it into the telescope.
Various problems have been encountered in the testing of clamping and unclamping devices used to date because the components are equipped with lifting handles of two different thicknesses, these thicknesses being typically 1/4" and 3/4". Further, these thicknesses vary as much as .+-.0.030" between handles of the same relative size. In order to compensate for these differences, previously suggested clamping devices required the astronaut to modify the clamping device, while in space, to accommodate the particular handle of a component being replaced. This task of modifying the clamping device occupied time which could be more constructively utilized. Further, the designs of the suggested clamping devices were not able to securely hold the lifting handles of the components because of the minor variations in handle thicknesses. As stated, because some of the components to be replaced are particularly large and cumbersome (approximately the size of a phone booth), large loads were imposed on the clamping devices by a leverage effect. In some cases, these loads were able to force open the latches of the clamping devices, freeing the handles and allowing the component to drift free, an obviously dangerous situation.
It is, therefore, an object of this invention to provide a clamping device which requires no modification by an astronaut and which will securely grip a lifting handle of a component.
It is a further object of this invention to provide a clamping device in which the latches cannot be forced open and which is simple in its use, requiring only one hand to operate.